def test_col_replace_w_constraint(self):
m = MetaData()
a = Table('a', m, Column('id', Integer, primary_key=True))
aid = Column('a_id', ForeignKey('a.id'))
b = Table('b', m, aid)
b.append_column(aid)
assert b.c.a_id.references(a.c.id)
eq_(len(b.constraints), 2)
